FUNCTIONAL-ACTIVITY OF BRONCHI FROM AN ORGAN DONOR WITH FATAL ASTHMA - STUDIES ON CRYOPRESERVED BRONCHI

Human bronchi were taken from the lungs of a single asthmatic and 5 no nasthmatic organ donors. The tissues were slowly frozen to -70 degrees C and stored for 1-28 months in liquid nitrogen (-196 degrees C) whil e suspended in Krebs-Henseleit solution containing 1.8 M dimethyl sulf oxide and 0.1 M sucrose as cryoprotectants. After thawing, bronchial r ings were suspended in 10 ml organ baths for isometric tension recordi ng. Spontaneously developed tone (1.13 +/- 0.12, n = 22, vs. 0.56 +/- 0.07 g, n = 33, p < 0.001) and maximal contractile responses to histam ine (1.93 +/- 0.12, n = 34, vs. 1.02 +/- 0.14 g, n = 30, p < 0.001) we re significantly stronger in asthmatic than in nonasthmatic bronchi. T he potency of histamine was 4 times less in asthmatic than in nonasthm atic bronchi (p < 0.001). Comparison of the maximal responses to hista mine after storage at -196 degrees C for up to 28 months revealed no s ignificant reduction of the contractile function by time of cryostorag e. Salbutamol and the potassium channel opener SDZ PCO 400 were 3-4 ti mes less potent in asthmatic than in nonasthmatic bronchi. For antagon ism of histamine by ketotifen in asthmatic bronchi (pD'(2) = 8.04 +/- 0.13, n = 5) 4 times higher concentrations were necessary than in nona sthmatic bronchi (pD'(2) = 8.63 +/- 0.06, n = 15, p < 0.001). These da ta support the contention that in spite of a diminished sensitivity to histamine after fatal asthma, isolated bronchi show enhanced spontane ous and agonist-induced contractile responses whereas relaxant respons es appear to be impaired.